Newbie question, rig character with skeleton from a different model
Yes, you can use a skeleton for another model. You'll need to skin your mesh to that armature. But this is the same for any rigging you do in blender. Google about skinning in blender.
If your rig doesn't fit your new model, you have to adjust it. If it's a simple rig with no complex constraints, hidden bones' layers, it would be an easy task, but if it's something like rigify rig, makeHuman rig, or any other complex rig, it would not be so easy. Those complex rigs are made with metarigs, then generated with scripts. So you will need to fit the source metarig to your new model, then re-generate the actual rig.